This application claims the priority of German patent document 197 03 488.8, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a process for measuring the relative movement of at least two components.
The measuring of the relative movement of components with respect to one another is important wherever these components interact with one another. Operations in which such interactions occur, for example, are engaging operations in clutches, the moving of a tooth of a gear wheel into the tooth space of a second gear wheel, displacements of meshing gearwheels under load, bending of shafts and bodies, and many other operations. Such measurements are carried out in order to more closely examine the course of the observed event.
In this context, very high demands are made on the measuring precision. In addition, the analysis of the measuring value becomes difficult, particularly when the observed components are moved not only with respect to one another but each component is also moved separately. Other components which cannot be measured by measuring techniques also influence the sequence of movements. In brief, the analysis of the measuring values becomes difficult because several parameters influencing the sequence of movements must be analyzed simultaneously.
The measuring of the synchronizing operation when a gear in a synchronized vehicle transmission is engaged, which so far has been difficult, can be used for demonstrating this problem:
A known observation of this operation by visual methods presents problems because the corresponding components move fast and observing them is difficult because of the excess oil.
In a known detection of the rotating movements by corresponding angular momentum generators, because of the rotational speed level as well as the measuring inaccuracies of the rotational speed generators, the actual event of the synchronization which takes place in a range of smaller changes of the detected signals is difficult to identify and analyze.
The moving direction of individual components can briefly change during the contact. Direction change is difficult to reproduce by conventional illustration methods, for example, line recording of the rotational speeds.
As a rule, the contact of components causes a change in the movement direction or a change of their speed. In the case of rotating components, this momentum change is normally detected by measuring techniques as a change of the rotational speed. Without any further analysis, this often brief change of rotational speed provides little information regarding the direction of force, angular change or contact points.
These and other objects and advantages are achieved by the measurement process according to the invention in which, after detecting the series of measuring values, while first taking into account known marginal conditions, at least a portion of the series of measuring values is adjusted by a mutual linking. By using known marginal conditions during the adjustment of the series of measuring values, the precision of the measurement is clearly improved using simple devices and without any additional expenditures with respect to the sensor assembly or the measuring process. As a result of the marginal conditions, the relationship of the measuring value in the range of the marginal conditions is known precisely or nearly so.
Furthermore, by means of a subsequent standardization of the series of measuring values, as required, the reference system, that is, the location of the observer of the measurement is freely selectable so that it is possible to observe the event from a particularly suitable reference system. The common representation of the series of measuring values precisely defines the relative movement of the components to be observed so that, on the whole, an analysis of the measurement is possible. This improves the precision and its ability to be analyzed.
An example of an adjustment while taking into account suitable marginal conditions is the following: If, during a measurement, two components, in this case, two gear wheels, move at precisely the same speed because they mesh with one another without slip, as a rule, a different rotating speed of a few rotations per minute is sensed as the measured quantity. This rotational speed difference, which differs from the actual value, has its causes in the measuring precision of the measuring chain of both components which is finitely limited and is within a permissible tolerance (see also FIG. 3). The speed difference, which is determined for reasons of a measuring inaccuracy, is computed as an "offset" from the mathematical difference of both signals and is added to the numerical values of the measured speed of at least one of the two components. Only a time range may be used for the speed adjustment in which the above-mentioned marginal conditions (speed equality) are valid. This ensures that the numerical values of both speeds, on the average, exhibit no relative deviations. The speed offset can be determined very precisely when one copy of the measuring series is smoothed by means of a digital (e.g., Butterworth) low-pass frequency of approximately 5% of the used sensing frequency and the difference is formed from the smoothed signals. The speed adjustment is permissible only if the measuring chains of the measured components are within the tolerance of a required measuring accuracy and within the measuring range valid for the respective measuring chain (outside an unacceptable limit range). In addition, it must be ensured that the measuring value sensing system has no aliasing effects or other systematic disturbances.
It is suggested to first calculate a position of the components from the series of measuring values. For this purpose, the pertaining movement or rotations are normally computed from the numerical values of the measured speeds or rotational speeds by means of a time-related integration. From the numerical values of the measured accelerations, the pertaining movement or rotations are calculated by a double time-related integration. In the case of each of these integrations, an integration constant will occur which is determined by the marginal conditions and is fixed to suitable values. This results in a positional adjustment of the components. The following is a corresponding example: By means of the present invention, the angle of rotation of mutually meshing components can be determined (for example, in the case of synchronous couplings), from the integration of the rotational speeds. The integration constants will be determined such that, at a selected point in time, where the components mesh with one another, the angle of rotation of the first components is 0.degree. and the angle of rotation of the second component amounts to the matching angular pitch. Thus, a penetration of the bodies is impossible. The position of both components is therefore determined.
If, as suggested, the marginal conditions for adjusting the series of measuring values are selected such that these marginal conditions are within the range of an event to be observed, that is, are valid in this range, the precision is increased exactly where the key point of the observation is situated. All conditions may be used as marginal conditions which increase the analysis and measuring precision.
To standardize the measuring values, it is suggested to use one of the series of measuring values. In this approach, the observer's location is identical with that component whose measuring values, such as its rotational movement, were used for the standardizing.
As an alternative, it is suggested to use a fixed value for the standardizing. In this approach, the observer takes up an apparently fixed location. It would be particularly advantageous if, in addition, this fixed value were to be selected from one of the series of measuring values. The reason is that the location of the observer would correspond to the position or movement of an observed component at a fixed point in time. Thus, changes of speed and direction relative to the reference system of the observed moved component become particularly easily visible.
In addition to the measured parameters, while utilizing geometric and physical marginal conditions, the position of additional components can be estimated with high precision and can be determined by means of the same method.
For the joint representation of the series of standardized measuring values, it is suggested to represent these as time-parallel lines in a diagram form. This permits a direct comparison of the different series of measuring values and an analysis of the measurement.
As an alternative, it is suggested that photo-realistic computer graphics or images, which are moved (that is, animated) by means of the series of standardized measuring values, be used for the representation of the observed components. In this case, it is particularly advantageous that also complex operations with different movements, such as combined rotational and longitudinal movements, are also represented in a clear and simultaneous manner which clearly improves the analysis of the measurement. The visual display permits an additional plausibility control of all measured parameters and provides a deeper understanding of the measured operation. By means of a perspectively correct display of the geometry, critical contact points can be recognized and clues can be obtained therefrom for constructive measures.
In this type of display, it is possible to change the visual characteristics of the objects used for the display or to select them such that additional information can be obtained. Thus, for example, a transparent or cut-open display of a sliding sleeve permits viewing the components disposed underneath or reviewing the engaging range of the toothings.
An observation in order to compare the different operations is also possible, whether in a time sequence (in order to determine the consequences of wear) or after constructive changes in that the different displays are stored and are then displayed in a time-parallel manner. The suggested process is particularly suitable for the comparison of a simulation and a measurement since the same method will now be used for the display. For the same reason, it will now also be particularly simple to integrate the results of the measurement into a CAD-system or a CAD-display.
It must be appreciated that such a clear type of display considerably facilitates the understanding of the observed movement sequences, provides visual information about movement dynamics and contact points and facilitates the fast introduction into the topics. This understanding results in ideas concerning solutions and suitable countermeasures.
The illustrated process may also be used for measuring the relative movement during the synchronizing of a clutch. This application is particularly advantageous because the synchronization operation has superimposed rotational and sliding movements of several components; specifically, the movements of the components pinion shaft, loose wheel and sliding sleeve. The pinion shaft component includes a synchronizing ring which is connected with it. Because of the shape of the components, these movements are subject to geometric marginal conditions and an analysis of the measurement is possible only when simultaneously considering all movements. Thus, within the framework of the application suggested here, as a marginal condition for the linking of the series of measuring values, it is assumed that, in the engaged condition, the rotational speeds of the pinion shaft, the fixed wheel and the loose wheel are identical and that the position of the sliding sleeve in the engaged condition is known.
The suggested application can be further improved particularly with respect to the representation and the ability of the measurement to be analyzed, if the rotational speeds of the pinion shaft and of the loose wheel takes place on the basis of one of the two rotational speeds. The representation of the component movement takes place relative to a standardized movement. Because of the standardizing, the component whose series of measuring values is used for the standardizing appears to be stationary so that the movements of the other components can be observed precisely. This is advantageous particularly in the range of the final synchronization.
In this context, it was found to be particularly advantageous to use for the standardization not a series of measuring values but the rotational speed of the clutch, that is, the rotational speed of one of its components in the engaged condition as a fixed measuring value. The location of the observer is now the synchronizing rotational speed so that movements of the pinion shaft connected with the vehicle mass, as well as of the loose wheel during the actual synchronizing operation, are displayed In particular, it is also possible, in this case, to display or to recognize a vibration of the pinion shaft. In the display, the components seem to virtually move into the synchronization operation.
On the whole, the present invention provides not only a process, but an application of this process which is very useful in the case of new developments during the elimination of series-related problems. As a result, it is possible to rapidly implement the identification of causes, recognition of operating mechanisms and the development of remedial measures.